Is an Ultracapacitor a Battery? And Other Basic Questions Answered

May 18, 2015 | Dennis Flynn, Director of Corporate Marketing

Most people know what a battery is, but not everyone is familiar with ultracapacitors. If you are just discovering ultracapacitor technology, this article will answer some of the most common questions asked about ultracapacitors.

Is an ultracapacitor a battery? No, it’s not. The main difference between ultracapacitors and batteries is in how they store energy. Batteries produce and store energy by means of a chemical reaction. Ultracapacitors store energy in an electric field.

To understand the difference in how they work, consider this simple analogy: A battery is like a garden hose—it provides low power for a long time. Batteries have higher energy density, but lower power density. An ultracapacitor is like a fire hose—it provides high power for a short time. Ultracapacitors have lower energy density but higher power density.

Do ultracapacitors replace batteries?
For the most part, ultracapacitors and batteries are complementary technologies, and it is more common for them to be paired to create a more effective solution. However, there are instances where an ultracapacitor will replace a battery, such as in certain wind, UPS and truck applications. The power of ultracapacitors combined with the energy of batteries can enable rapid response times, extend operational temperature range and lengthen battery life by up to two times.

Are ultracapacitors the same as capacitors?
Nope, they are also two different things. Ultracapacitors can store 1,000 times more energy and sustain output for much longer than conventional capacitors.

Has ultracapacitor technology been proven in the field? Yes. Ultracapacitors serve in applications and industries around the world. Millions of ultracapacitors are installed in cars, buses, data centers and wind turbines to extend battery life, increase reliability, energy-efficiency, and to reduce maintenance.

How does ultracapacitor cost compare to the cost of batteries?Although ultracapacitors can require a higher up-front investment than batteries, they offer a larger return on investment over their lifetime. Batteries need maintenance and replacement much more frequently than the rugged ultracapacitor, which provides hundreds of thousands of charge/discharge cycles where batteries can only perform thousands of charge/discharge cycles. Ultracapacitors are not as vulnerable to extreme weather conditions—batteries are typically damaged by excessive heat or they quit operating when exposed to extreme cold. Over the past decade, prices for ultracapacitors have fallen at a much faster rate than the price of batteries, so industries investing in ultracapacitor technology can expect to benefit from lower prices and higher ROI compared to batteries.

Ultracapacitors are truly the unsung heroes in energy storage technology. Batteries have been around much longer, but a wide array of industries are designing-in ultracapacitors in a variety of unique applications, taking advantage of ultracapacitor power and efficiency.

Dennis Flynn has been with Maxwell Technologies, Inc. for four years as Director of Corporate Marketing. Prior to joining Maxwell he authored a book on branding called Brand Clout: Maintaining Relevance & Profitability Amidst Constant Change. He founded two companies focused on strategic marketing and has consulted with prestigious technology firms such as Toshiba and Gateway Computers. He also served as a Senior Fellow at The Media Center in Washington, D.C.

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